180daa560SRoman Zippelconfig ARCH 280daa560SRoman Zippel string 380daa560SRoman Zippel option env="ARCH" 480daa560SRoman Zippel 580daa560SRoman Zippelconfig KERNELVERSION 680daa560SRoman Zippel string 780daa560SRoman Zippel option env="KERNELVERSION" 880daa560SRoman Zippel 9face4374SRoman Zippelconfig DEFCONFIG_LIST 10face4374SRoman Zippel string 11b2670eacSPaolo 'Blaisorblade' Giarrusso depends on !UML 12face4374SRoman Zippel option defconfig_list 13face4374SRoman Zippel default "/lib/modules/$UNAME_RELEASE/.config" 14face4374SRoman Zippel default "/etc/kernel-config" 15face4374SRoman Zippel default "/boot/config-$UNAME_RELEASE" 1673531905SSam Ravnborg default "$ARCH_DEFCONFIG" 17face4374SRoman Zippel default "arch/$ARCH/defconfig" 18face4374SRoman Zippel 19ff0cfc66SAl Boldimenu "General setup" 201da177e4SLinus Torvalds 211da177e4SLinus Torvaldsconfig EXPERIMENTAL 221da177e4SLinus Torvalds bool "Prompt for development and/or incomplete code/drivers" 231da177e4SLinus Torvalds ---help--- 241da177e4SLinus Torvalds Some of the various things that Linux supports (such as network 251da177e4SLinus Torvalds drivers, file systems, network protocols, etc.) can be in a state 261da177e4SLinus Torvalds of development where the functionality, stability, or the level of 271da177e4SLinus Torvalds testing is not yet high enough for general use. This is usually 281da177e4SLinus Torvalds known as the "alpha-test" phase among developers. If a feature is 291da177e4SLinus Torvalds currently in alpha-test, then the developers usually discourage 301da177e4SLinus Torvalds uninformed widespread use of this feature by the general public to 311da177e4SLinus Torvalds avoid "Why doesn't this work?" type mail messages. However, active 321da177e4SLinus Torvalds testing and use of these systems is welcomed. Just be aware that it 331da177e4SLinus Torvalds may not meet the normal level of reliability or it may fail to work 341da177e4SLinus Torvalds in some special cases. Detailed bug reports from people familiar 351da177e4SLinus Torvalds with the kernel internals are usually welcomed by the developers 361da177e4SLinus Torvalds (before submitting bug reports, please read the documents 371da177e4SLinus Torvalds <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 381da177e4SLinus Torvalds <file:Documentation/BUG-HUNTING>, and 391da177e4SLinus Torvalds <file:Documentation/oops-tracing.txt> in the kernel source). 401da177e4SLinus Torvalds 411da177e4SLinus Torvalds This option will also make obsoleted drivers available. These are 421da177e4SLinus Torvalds drivers that have been replaced by something else, and/or are 431da177e4SLinus Torvalds scheduled to be removed in a future kernel release. 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds Unless you intend to help test and develop a feature or driver that 461da177e4SLinus Torvalds falls into this category, or you have a situation that requires 471da177e4SLinus Torvalds using these features, you should probably say N here, which will 481da177e4SLinus Torvalds cause the configurator to present you with fewer choices. If 491da177e4SLinus Torvalds you say Y here, you will be offered the choice of using features or 501da177e4SLinus Torvalds drivers that are currently considered to be in the alpha-test phase. 511da177e4SLinus Torvalds 521da177e4SLinus Torvaldsconfig BROKEN 531da177e4SLinus Torvalds bool 541da177e4SLinus Torvalds 551da177e4SLinus Torvaldsconfig BROKEN_ON_SMP 561da177e4SLinus Torvalds bool 571da177e4SLinus Torvalds depends on BROKEN || !SMP 581da177e4SLinus Torvalds default y 591da177e4SLinus Torvalds 601da177e4SLinus Torvaldsconfig LOCK_KERNEL 611da177e4SLinus Torvalds bool 621da177e4SLinus Torvalds depends on SMP || PREEMPT 631da177e4SLinus Torvalds default y 641da177e4SLinus Torvalds 651da177e4SLinus Torvaldsconfig INIT_ENV_ARG_LIMIT 661da177e4SLinus Torvalds int 67dd673bcaSAdrian Bunk default 32 if !UML 68dd673bcaSAdrian Bunk default 128 if UML 691da177e4SLinus Torvalds help 7034ad92c2SRandy Dunlap Maximum of each of the number of arguments and environment 7134ad92c2SRandy Dunlap variables passed to init from the kernel command line. 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds 741da177e4SLinus Torvaldsconfig LOCALVERSION 751da177e4SLinus Torvalds string "Local version - append to kernel release" 761da177e4SLinus Torvalds help 771da177e4SLinus Torvalds Append an extra string to the end of your kernel version. 781da177e4SLinus Torvalds This will show up when you type uname, for example. 791da177e4SLinus Torvalds The string you set here will be appended after the contents of 801da177e4SLinus Torvalds any files with a filename matching localversion* in your 811da177e4SLinus Torvalds object and source tree, in that order. Your total string can 821da177e4SLinus Torvalds be a maximum of 64 characters. 831da177e4SLinus Torvalds 84aaebf433SRyan Andersonconfig LOCALVERSION_AUTO 85aaebf433SRyan Anderson bool "Automatically append version information to the version string" 86aaebf433SRyan Anderson default y 87aaebf433SRyan Anderson help 88aaebf433SRyan Anderson This will try to automatically determine if the current tree is a 896e5a5420SRobert P. J. Day release tree by looking for git tags that belong to the current 906e5a5420SRobert P. J. Day top of tree revision. 91aaebf433SRyan Anderson 92aaebf433SRyan Anderson A string of the format -gxxxxxxxx will be added to the localversion 936e5a5420SRobert P. J. Day if a git-based tree is found. The string generated by this will be 94aaebf433SRyan Anderson appended after any matching localversion* files, and after the value 956e5a5420SRobert P. J. Day set in CONFIG_LOCALVERSION. 96aaebf433SRyan Anderson 976e5a5420SRobert P. J. Day (The actual string used here is the first eight characters produced 986e5a5420SRobert P. J. Day by running the command: 996e5a5420SRobert P. J. Day 1006e5a5420SRobert P. J. Day $ git rev-parse --verify HEAD 1016e5a5420SRobert P. J. Day 1026e5a5420SRobert P. J. Day which is done within the script "scripts/setlocalversion".) 103aaebf433SRyan Anderson 1041da177e4SLinus Torvaldsconfig SWAP 1051da177e4SLinus Torvalds bool "Support for paging of anonymous memory (swap)" 1069361401eSDavid Howells depends on MMU && BLOCK 1071da177e4SLinus Torvalds default y 1081da177e4SLinus Torvalds help 1091da177e4SLinus Torvalds This option allows you to choose whether you want to have support 1101da177e4SLinus Torvalds for so called swap devices or swap files in your kernel that are 1111da177e4SLinus Torvalds used to provide more virtual memory than the actual RAM present 1121da177e4SLinus Torvalds in your computer. If unsure say Y. 1131da177e4SLinus Torvalds 1141da177e4SLinus Torvaldsconfig SYSVIPC 1151da177e4SLinus Torvalds bool "System V IPC" 1161da177e4SLinus Torvalds ---help--- 1171da177e4SLinus Torvalds Inter Process Communication is a suite of library functions and 1181da177e4SLinus Torvalds system calls which let processes (running programs) synchronize and 1191da177e4SLinus Torvalds exchange information. It is generally considered to be a good thing, 1201da177e4SLinus Torvalds and some programs won't run unless you say Y here. In particular, if 1211da177e4SLinus Torvalds you want to run the DOS emulator dosemu under Linux (read the 1221da177e4SLinus Torvalds DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 1231da177e4SLinus Torvalds you'll need to say Y here. 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds You can find documentation about IPC with "info ipc" and also in 1261da177e4SLinus Torvalds section 6.4 of the Linux Programmer's Guide, available from 1271da177e4SLinus Torvalds <http://www.tldp.org/guides.html>. 1281da177e4SLinus Torvalds 129a5494dcdSEric W. Biedermanconfig SYSVIPC_SYSCTL 130a5494dcdSEric W. Biederman bool 131a5494dcdSEric W. Biederman depends on SYSVIPC 132a5494dcdSEric W. Biederman depends on SYSCTL 133a5494dcdSEric W. Biederman default y 134a5494dcdSEric W. Biederman 1351da177e4SLinus Torvaldsconfig POSIX_MQUEUE 1361da177e4SLinus Torvalds bool "POSIX Message Queues" 1371da177e4SLinus Torvalds depends on NET && EXPERIMENTAL 1381da177e4SLinus Torvalds ---help--- 1391da177e4SLinus Torvalds POSIX variant of message queues is a part of IPC. In POSIX message 1401da177e4SLinus Torvalds queues every message has a priority which decides about succession 1411da177e4SLinus Torvalds of receiving it by a process. If you want to compile and run 1421da177e4SLinus Torvalds programs written e.g. for Solaris with use of its POSIX message 143b0e37650SRobert P. J. Day queues (functions mq_*) say Y here. 1441da177e4SLinus Torvalds 1451da177e4SLinus Torvalds POSIX message queues are visible as a filesystem called 'mqueue' 1461da177e4SLinus Torvalds and can be mounted somewhere if you want to do filesystem 1471da177e4SLinus Torvalds operations on message queues. 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds If unsure, say Y. 1501da177e4SLinus Torvalds 1511da177e4SLinus Torvaldsconfig BSD_PROCESS_ACCT 1521da177e4SLinus Torvalds bool "BSD Process Accounting" 1531da177e4SLinus Torvalds help 1541da177e4SLinus Torvalds If you say Y here, a user level program will be able to instruct the 1551da177e4SLinus Torvalds kernel (via a special system call) to write process accounting 1561da177e4SLinus Torvalds information to a file: whenever a process exits, information about 1571da177e4SLinus Torvalds that process will be appended to the file by the kernel. The 1581da177e4SLinus Torvalds information includes things such as creation time, owning user, 1591da177e4SLinus Torvalds command name, memory usage, controlling terminal etc. (the complete 1601da177e4SLinus Torvalds list is in the struct acct in <file:include/linux/acct.h>). It is 1611da177e4SLinus Torvalds up to the user level program to do useful things with this 1621da177e4SLinus Torvalds information. This is generally a good idea, so say Y. 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvaldsconfig BSD_PROCESS_ACCT_V3 1651da177e4SLinus Torvalds bool "BSD Process Accounting version 3 file format" 1661da177e4SLinus Torvalds depends on BSD_PROCESS_ACCT 1671da177e4SLinus Torvalds default n 1681da177e4SLinus Torvalds help 1691da177e4SLinus Torvalds If you say Y here, the process accounting information is written 1701da177e4SLinus Torvalds in a new file format that also logs the process IDs of each 1711da177e4SLinus Torvalds process and it's parent. Note that this file format is incompatible 1721da177e4SLinus Torvalds with previous v0/v1/v2 file formats, so you will need updated tools 1731da177e4SLinus Torvalds for processing it. A preliminary version of these tools is available 17437a4c940SS.Çağlar Onur at <http://www.gnu.org/software/acct/>. 1751da177e4SLinus Torvalds 176c757249aSShailabh Nagarconfig TASKSTATS 177c757249aSShailabh Nagar bool "Export task/process statistics through netlink (EXPERIMENTAL)" 178c757249aSShailabh Nagar depends on NET 179c757249aSShailabh Nagar default n 180c757249aSShailabh Nagar help 181c757249aSShailabh Nagar Export selected statistics for tasks/processes through the 182c757249aSShailabh Nagar generic netlink interface. Unlike BSD process accounting, the 183c757249aSShailabh Nagar statistics are available during the lifetime of tasks/processes as 184c757249aSShailabh Nagar responses to commands. Like BSD accounting, they are sent to user 185c757249aSShailabh Nagar space on task exit. 186c757249aSShailabh Nagar 187c757249aSShailabh Nagar Say N if unsure. 188c757249aSShailabh Nagar 189ca74e92bSShailabh Nagarconfig TASK_DELAY_ACCT 190ca74e92bSShailabh Nagar bool "Enable per-task delay accounting (EXPERIMENTAL)" 1916f44993fSShailabh Nagar depends on TASKSTATS 192ca74e92bSShailabh Nagar help 193ca74e92bSShailabh Nagar Collect information on time spent by a task waiting for system 194ca74e92bSShailabh Nagar resources like cpu, synchronous block I/O completion and swapping 195ca74e92bSShailabh Nagar in pages. Such statistics can help in setting a task's priorities 196ca74e92bSShailabh Nagar relative to other tasks for cpu, io, rss limits etc. 197ca74e92bSShailabh Nagar 198ca74e92bSShailabh Nagar Say N if unsure. 199ca74e92bSShailabh Nagar 20018f705f4SAlexey Dobriyanconfig TASK_XACCT 20118f705f4SAlexey Dobriyan bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 20218f705f4SAlexey Dobriyan depends on TASKSTATS 20318f705f4SAlexey Dobriyan help 20418f705f4SAlexey Dobriyan Collect extended task accounting data and send the data 20518f705f4SAlexey Dobriyan to userland for processing over the taskstats interface. 20618f705f4SAlexey Dobriyan 20718f705f4SAlexey Dobriyan Say N if unsure. 20818f705f4SAlexey Dobriyan 20918f705f4SAlexey Dobriyanconfig TASK_IO_ACCOUNTING 21018f705f4SAlexey Dobriyan bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 21118f705f4SAlexey Dobriyan depends on TASK_XACCT 21218f705f4SAlexey Dobriyan help 21318f705f4SAlexey Dobriyan Collect information on the number of bytes of storage I/O which this 21418f705f4SAlexey Dobriyan task has caused. 21518f705f4SAlexey Dobriyan 21618f705f4SAlexey Dobriyan Say N if unsure. 21718f705f4SAlexey Dobriyan 2181da177e4SLinus Torvaldsconfig AUDIT 2191da177e4SLinus Torvalds bool "Auditing support" 220804a6a49SChris Wright depends on NET 2211da177e4SLinus Torvalds help 2221da177e4SLinus Torvalds Enable auditing infrastructure that can be used with another 2231da177e4SLinus Torvalds kernel subsystem, such as SELinux (which requires this for 2241da177e4SLinus Torvalds logging of avc messages output). Does not do system-call 2251da177e4SLinus Torvalds auditing without CONFIG_AUDITSYSCALL. 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvaldsconfig AUDITSYSCALL 2281da177e4SLinus Torvalds bool "Enable system-call auditing support" 2291322b9deSYuichi Nakamura depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH) 2301da177e4SLinus Torvalds default y if SECURITY_SELINUX 2311da177e4SLinus Torvalds help 2321da177e4SLinus Torvalds Enable low-overhead system-call auditing infrastructure that 2331da177e4SLinus Torvalds can be used independently or with another kernel subsystem, 234f368c07dSAmy Griffis such as SELinux. To use audit's filesystem watch feature, please 235f368c07dSAmy Griffis ensure that INOTIFY is configured. 2361da177e4SLinus Torvalds 23774c3cbe3SAl Viroconfig AUDIT_TREE 23874c3cbe3SAl Viro def_bool y 23974c3cbe3SAl Viro depends on AUDITSYSCALL && INOTIFY 24074c3cbe3SAl Viro 2411da177e4SLinus Torvaldsconfig IKCONFIG 242f2443ab6SRoss Biro tristate "Kernel .config support" 2431da177e4SLinus Torvalds ---help--- 2441da177e4SLinus Torvalds This option enables the complete Linux kernel ".config" file 2451da177e4SLinus Torvalds contents to be saved in the kernel. It provides documentation 2461da177e4SLinus Torvalds of which kernel options are used in a running kernel or in an 2471da177e4SLinus Torvalds on-disk kernel. This information can be extracted from the kernel 2481da177e4SLinus Torvalds image file with the script scripts/extract-ikconfig and used as 2491da177e4SLinus Torvalds input to rebuild the current kernel or to build another kernel. 2501da177e4SLinus Torvalds It can also be extracted from a running kernel by reading 2511da177e4SLinus Torvalds /proc/config.gz if enabled (below). 2521da177e4SLinus Torvalds 2531da177e4SLinus Torvaldsconfig IKCONFIG_PROC 2541da177e4SLinus Torvalds bool "Enable access to .config through /proc/config.gz" 2551da177e4SLinus Torvalds depends on IKCONFIG && PROC_FS 2561da177e4SLinus Torvalds ---help--- 2571da177e4SLinus Torvalds This option enables access to the kernel configuration file 2581da177e4SLinus Torvalds through /proc/config.gz. 2591da177e4SLinus Torvalds 260794543a2SAlistair John Strachanconfig LOG_BUF_SHIFT 261794543a2SAlistair John Strachan int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 262794543a2SAlistair John Strachan range 12 21 263f17a32e9SAdrian Bunk default 17 264794543a2SAlistair John Strachan help 265794543a2SAlistair John Strachan Select kernel log buffer size as a power of 2. 266f17a32e9SAdrian Bunk Examples: 267f17a32e9SAdrian Bunk 17 => 128 KB 268f17a32e9SAdrian Bunk 16 => 64 KB 269f17a32e9SAdrian Bunk 15 => 32 KB 270f17a32e9SAdrian Bunk 14 => 16 KB 271794543a2SAlistair John Strachan 13 => 8 KB 272794543a2SAlistair John Strachan 12 => 4 KB 273794543a2SAlistair John Strachan 274ddbcc7e8SPaul Menageconfig CGROUPS 275ddbcc7e8SPaul Menage bool "Control Group support" 276ddbcc7e8SPaul Menage help 277ddbcc7e8SPaul Menage This option will let you use process cgroup subsystems 278ddbcc7e8SPaul Menage such as Cpusets 279ddbcc7e8SPaul Menage 280ddbcc7e8SPaul Menage Say N if unsure. 281ddbcc7e8SPaul Menage 282006cb992SPaul Menageconfig CGROUP_DEBUG 283006cb992SPaul Menage bool "Example debug cgroup subsystem" 284006cb992SPaul Menage depends on CGROUPS 285418d7d87SPaul Menage default n 286006cb992SPaul Menage help 287006cb992SPaul Menage This option enables a simple cgroup subsystem that 288006cb992SPaul Menage exports useful debugging information about the cgroups 289006cb992SPaul Menage framework 290006cb992SPaul Menage 291006cb992SPaul Menage Say N if unsure 292006cb992SPaul Menage 293858d72eaSSerge E. Hallynconfig CGROUP_NS 294858d72eaSSerge E. Hallyn bool "Namespace cgroup subsystem" 295858d72eaSSerge E. Hallyn depends on CGROUPS 296858d72eaSSerge E. Hallyn help 297858d72eaSSerge E. Hallyn Provides a simple namespace cgroup subsystem to 298858d72eaSSerge E. Hallyn provide hierarchical naming of sets of namespaces, 299858d72eaSSerge E. Hallyn for instance virtual servers and checkpoint/restart 300858d72eaSSerge E. Hallyn jobs. 301858d72eaSSerge E. Hallyn 302*dc52ddc0SMatt Helsleyconfig CGROUP_FREEZER 303*dc52ddc0SMatt Helsley bool "control group freezer subsystem" 304*dc52ddc0SMatt Helsley depends on CGROUPS 305*dc52ddc0SMatt Helsley help 306*dc52ddc0SMatt Helsley Provides a way to freeze and unfreeze all tasks in a 307*dc52ddc0SMatt Helsley cgroup. 308*dc52ddc0SMatt Helsley 30908ce5f16SSerge E. Hallynconfig CGROUP_DEVICE 31008ce5f16SSerge E. Hallyn bool "Device controller for cgroups" 31108ce5f16SSerge E. Hallyn depends on CGROUPS && EXPERIMENTAL 31208ce5f16SSerge E. Hallyn help 31308ce5f16SSerge E. Hallyn Provides a cgroup implementing whitelists for devices which 31408ce5f16SSerge E. Hallyn a process in the cgroup can mknod or open. 31508ce5f16SSerge E. Hallyn 3161da177e4SLinus Torvaldsconfig CPUSETS 3171da177e4SLinus Torvalds bool "Cpuset support" 3188793d854SPaul Menage depends on SMP && CGROUPS 3191da177e4SLinus Torvalds help 320d9fd8a6dSRandy Dunlap This option will let you create and manage CPUSETs which 3211da177e4SLinus Torvalds allow dynamically partitioning a system into sets of CPUs and 3221da177e4SLinus Torvalds Memory Nodes and assigning tasks to run only within those sets. 3231da177e4SLinus Torvalds This is primarily useful on large SMP or NUMA systems. 3241da177e4SLinus Torvalds 3251da177e4SLinus Torvalds Say N if unsure. 3261da177e4SLinus Torvalds 327a5574cf6SIngo Molnar# 328a5574cf6SIngo Molnar# Architectures with an unreliable sched_clock() should select this: 329a5574cf6SIngo Molnar# 330a5574cf6SIngo Molnarconfig HAVE_UNSTABLE_SCHED_CLOCK 331a5574cf6SIngo Molnar bool 332a5574cf6SIngo Molnar 333052f1dc7SPeter Zijlstraconfig GROUP_SCHED 334052f1dc7SPeter Zijlstra bool "Group CPU scheduler" 335aac6abcaSParag Warudkar depends on EXPERIMENTAL 336aac6abcaSParag Warudkar default n 33729f59db3SSrivatsa Vaddagiri help 338fb615581SSrivatsa Vaddagiri This feature lets CPU scheduler recognize task groups and control CPU 3399b5b7751SSrivatsa Vaddagiri bandwidth allocation to such task groups. 34029f59db3SSrivatsa Vaddagiri 341052f1dc7SPeter Zijlstraconfig FAIR_GROUP_SCHED 342052f1dc7SPeter Zijlstra bool "Group scheduling for SCHED_OTHER" 343052f1dc7SPeter Zijlstra depends on GROUP_SCHED 344aac6abcaSParag Warudkar default GROUP_SCHED 34524e377a8SSrivatsa Vaddagiri 346052f1dc7SPeter Zijlstraconfig RT_GROUP_SCHED 347052f1dc7SPeter Zijlstra bool "Group scheduling for SCHED_RR/FIFO" 348052f1dc7SPeter Zijlstra depends on EXPERIMENTAL 349052f1dc7SPeter Zijlstra depends on GROUP_SCHED 350052f1dc7SPeter Zijlstra default n 351b9b158feSViktor Radnai help 352b9b158feSViktor Radnai This feature lets you explicitly allocate real CPU bandwidth 353b9b158feSViktor Radnai to users or control groups (depending on the "Basis for grouping tasks" 354b9b158feSViktor Radnai setting below. If enabled, it will also make it impossible to 355b9b158feSViktor Radnai schedule realtime tasks for non-root users until you allocate 356b9b158feSViktor Radnai realtime bandwidth for them. 357b9b158feSViktor Radnai See Documentation/sched-rt-group.txt for more information. 358052f1dc7SPeter Zijlstra 359052f1dc7SPeter Zijlstrachoice 360052f1dc7SPeter Zijlstra depends on GROUP_SCHED 361052f1dc7SPeter Zijlstra prompt "Basis for grouping tasks" 362052f1dc7SPeter Zijlstra default USER_SCHED 363052f1dc7SPeter Zijlstra 364052f1dc7SPeter Zijlstraconfig USER_SCHED 36524e377a8SSrivatsa Vaddagiri bool "user id" 36624e377a8SSrivatsa Vaddagiri help 36724e377a8SSrivatsa Vaddagiri This option will choose userid as the basis for grouping 368fb615581SSrivatsa Vaddagiri tasks, thus providing equal CPU bandwidth to each user. 36924e377a8SSrivatsa Vaddagiri 370052f1dc7SPeter Zijlstraconfig CGROUP_SCHED 37168318b8eSSrivatsa Vaddagiri bool "Control groups" 37268318b8eSSrivatsa Vaddagiri depends on CGROUPS 37368318b8eSSrivatsa Vaddagiri help 37468318b8eSSrivatsa Vaddagiri This option allows you to create arbitrary task groups 37568318b8eSSrivatsa Vaddagiri using the "cgroup" pseudo filesystem and control 37668318b8eSSrivatsa Vaddagiri the cpu bandwidth allocated to each such task group. 37768318b8eSSrivatsa Vaddagiri Refer to Documentation/cgroups.txt for more information 37868318b8eSSrivatsa Vaddagiri on "cgroup" pseudo filesystem. 37968318b8eSSrivatsa Vaddagiri 38024e377a8SSrivatsa Vaddagiriendchoice 38124e377a8SSrivatsa Vaddagiri 382d842de87SSrivatsa Vaddagiriconfig CGROUP_CPUACCT 383d842de87SSrivatsa Vaddagiri bool "Simple CPU accounting cgroup subsystem" 384d842de87SSrivatsa Vaddagiri depends on CGROUPS 385d842de87SSrivatsa Vaddagiri help 386d842de87SSrivatsa Vaddagiri Provides a simple Resource Controller for monitoring the 387d842de87SSrivatsa Vaddagiri total CPU consumed by the tasks in a cgroup 388d842de87SSrivatsa Vaddagiri 389e552b661SPavel Emelianovconfig RESOURCE_COUNTERS 390e552b661SPavel Emelianov bool "Resource counters" 391e552b661SPavel Emelianov help 392e552b661SPavel Emelianov This option enables controller independent resource accounting 393e552b661SPavel Emelianov infrastructure that works with cgroups 394e552b661SPavel Emelianov depends on CGROUPS 395e552b661SPavel Emelianov 396cf475ad2SBalbir Singhconfig MM_OWNER 397cf475ad2SBalbir Singh bool 398cf475ad2SBalbir Singh 39900f0b825SBalbir Singhconfig CGROUP_MEM_RES_CTLR 40000f0b825SBalbir Singh bool "Memory Resource Controller for Control Groups" 40100f0b825SBalbir Singh depends on CGROUPS && RESOURCE_COUNTERS 402cf475ad2SBalbir Singh select MM_OWNER 40300f0b825SBalbir Singh help 40400f0b825SBalbir Singh Provides a memory resource controller that manages both page cache and 40500f0b825SBalbir Singh RSS memory. 40600f0b825SBalbir Singh 40700f0b825SBalbir Singh Note that setting this option increases fixed memory overhead 40800f0b825SBalbir Singh associated with each page of memory in the system by 4/8 bytes 40900f0b825SBalbir Singh and also increases cache misses because struct page on many 64bit 41000f0b825SBalbir Singh systems will not fit into a single cache line anymore. 41100f0b825SBalbir Singh 41200f0b825SBalbir Singh Only enable when you're ok with these trade offs and really 41300f0b825SBalbir Singh sure you need the memory resource controller. 41400f0b825SBalbir Singh 415cf475ad2SBalbir Singh This config option also selects MM_OWNER config option, which 416cf475ad2SBalbir Singh could in turn add some fork/exit overhead. 417cf475ad2SBalbir Singh 41888a22c98SKay Sieversconfig SYSFS_DEPRECATED 419d47846c5SIngo Molnar bool 420d47846c5SIngo Molnar 421d47846c5SIngo Molnarconfig SYSFS_DEPRECATED_V2 42288a22c98SKay Sievers bool "Create deprecated sysfs files" 4239148fe87SRandy Dunlap depends on SYSFS 42488a22c98SKay Sievers default y 425d47846c5SIngo Molnar select SYSFS_DEPRECATED 42688a22c98SKay Sievers help 42788a22c98SKay Sievers This option creates deprecated symlinks such as the 42888a22c98SKay Sievers "device"-link, the <subsystem>:<name>-link, and the 42988a22c98SKay Sievers "bus"-link. It may also add deprecated key in the 43088a22c98SKay Sievers uevent environment. 43188a22c98SKay Sievers None of these features or values should be used today, as 43288a22c98SKay Sievers they export driver core implementation details to userspace 43388a22c98SKay Sievers or export properties which can't be kept stable across kernel 43488a22c98SKay Sievers releases. 43588a22c98SKay Sievers 43688a22c98SKay Sievers If enabled, this option will also move any device structures 4373dde6ad8SDavid Sterba that belong to a class, back into the /sys/class hierarchy, in 438024440d2SGreg Kroah-Hartman order to support older versions of udev and some userspace 439024440d2SGreg Kroah-Hartman programs. 44088a22c98SKay Sievers 441024440d2SGreg Kroah-Hartman If you are using a distro with the most recent userspace 442024440d2SGreg Kroah-Hartman packages, it should be safe to say N here. 44388a22c98SKay Sievers 4448793d854SPaul Menageconfig PROC_PID_CPUSET 4458793d854SPaul Menage bool "Include legacy /proc/<pid>/cpuset file" 4468793d854SPaul Menage depends on CPUSETS 4478793d854SPaul Menage default y 4488793d854SPaul Menage 449b86ff981SJens Axboeconfig RELAY 450b86ff981SJens Axboe bool "Kernel->user space relay support (formerly relayfs)" 451b86ff981SJens Axboe help 452b86ff981SJens Axboe This option enables support for relay interface support in 453b86ff981SJens Axboe certain file systems (such as debugfs). 454b86ff981SJens Axboe It is designed to provide an efficient mechanism for tools and 455b86ff981SJens Axboe facilities to relay large amounts of data from kernel space to 456b86ff981SJens Axboe user space. 457b86ff981SJens Axboe 458b86ff981SJens Axboe If unsure, say N. 459b86ff981SJens Axboe 460c5289a69SPavel Emelyanovconfig NAMESPACES 461c5289a69SPavel Emelyanov bool "Namespaces support" if EMBEDDED 462c5289a69SPavel Emelyanov default !EMBEDDED 463c5289a69SPavel Emelyanov help 464c5289a69SPavel Emelyanov Provides the way to make tasks work with different objects using 465c5289a69SPavel Emelyanov the same id. For example same IPC id may refer to different objects 466c5289a69SPavel Emelyanov or same user id or pid may refer to different tasks when used in 467c5289a69SPavel Emelyanov different namespaces. 468c5289a69SPavel Emelyanov 46958bfdd6dSPavel Emelyanovconfig UTS_NS 47058bfdd6dSPavel Emelyanov bool "UTS namespace" 47158bfdd6dSPavel Emelyanov depends on NAMESPACES 47258bfdd6dSPavel Emelyanov help 47358bfdd6dSPavel Emelyanov In this namespace tasks see different info provided with the 47458bfdd6dSPavel Emelyanov uname() system call 47558bfdd6dSPavel Emelyanov 476ae5e1b22SPavel Emelyanovconfig IPC_NS 477ae5e1b22SPavel Emelyanov bool "IPC namespace" 478ae5e1b22SPavel Emelyanov depends on NAMESPACES && SYSVIPC 479ae5e1b22SPavel Emelyanov help 480ae5e1b22SPavel Emelyanov In this namespace tasks work with IPC ids which correspond to 481ae5e1b22SPavel Emelyanov different IPC objects in different namespaces 482ae5e1b22SPavel Emelyanov 483aee16ce7SPavel Emelyanovconfig USER_NS 484aee16ce7SPavel Emelyanov bool "User namespace (EXPERIMENTAL)" 485aee16ce7SPavel Emelyanov depends on NAMESPACES && EXPERIMENTAL 486aee16ce7SPavel Emelyanov help 487aee16ce7SPavel Emelyanov This allows containers, i.e. vservers, to use user namespaces 488aee16ce7SPavel Emelyanov to provide different user info for different servers. 489aee16ce7SPavel Emelyanov If unsure, say N. 490aee16ce7SPavel Emelyanov 49174bd59bbSPavel Emelyanovconfig PID_NS 49274bd59bbSPavel Emelyanov bool "PID Namespaces (EXPERIMENTAL)" 49374bd59bbSPavel Emelyanov default n 49474bd59bbSPavel Emelyanov depends on NAMESPACES && EXPERIMENTAL 49574bd59bbSPavel Emelyanov help 49612d2b8f9SHeikki Orsila Support process id namespaces. This allows having multiple 49774bd59bbSPavel Emelyanov process with the same pid as long as they are in different 49874bd59bbSPavel Emelyanov pid namespaces. This is a building block of containers. 49974bd59bbSPavel Emelyanov 50074bd59bbSPavel Emelyanov Unless you want to work with an experimental feature 50174bd59bbSPavel Emelyanov say N here. 50274bd59bbSPavel Emelyanov 503f991633dSDimitri Gorokhovikconfig BLK_DEV_INITRD 504f991633dSDimitri Gorokhovik bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 505f991633dSDimitri Gorokhovik depends on BROKEN || !FRV 506f991633dSDimitri Gorokhovik help 507f991633dSDimitri Gorokhovik The initial RAM filesystem is a ramfs which is loaded by the 508f991633dSDimitri Gorokhovik boot loader (loadlin or lilo) and that is mounted as root 509f991633dSDimitri Gorokhovik before the normal boot procedure. It is typically used to 510f991633dSDimitri Gorokhovik load modules needed to mount the "real" root file system, 511f991633dSDimitri Gorokhovik etc. See <file:Documentation/initrd.txt> for details. 512f991633dSDimitri Gorokhovik 513f991633dSDimitri Gorokhovik If RAM disk support (BLK_DEV_RAM) is also included, this 514f991633dSDimitri Gorokhovik also enables initial RAM disk (initrd) support and adds 515f991633dSDimitri Gorokhovik 15 Kbytes (more on some other architectures) to the kernel size. 516f991633dSDimitri Gorokhovik 517f991633dSDimitri Gorokhovik If unsure say Y. 518f991633dSDimitri Gorokhovik 519c33df4eaSJean-Paul Samanif BLK_DEV_INITRD 520c33df4eaSJean-Paul Saman 521dbec4866SSam Ravnborgsource "usr/Kconfig" 522dbec4866SSam Ravnborg 523c33df4eaSJean-Paul Samanendif 524c33df4eaSJean-Paul Saman 525c45b4f1fSLinus Torvaldsconfig CC_OPTIMIZE_FOR_SIZE 52696fffeb4SIngo Molnar bool "Optimize for size" 527c45b4f1fSLinus Torvalds default y 528c45b4f1fSLinus Torvalds help 529c45b4f1fSLinus Torvalds Enabling this option will pass "-Os" instead of "-O2" to gcc 530c45b4f1fSLinus Torvalds resulting in a smaller kernel. 531c45b4f1fSLinus Torvalds 532775a7229Sjkacur If unsure, say Y. 533c45b4f1fSLinus Torvalds 5340847062aSRandy Dunlapconfig SYSCTL 5350847062aSRandy Dunlap bool 5360847062aSRandy Dunlap 5371da177e4SLinus Torvaldsmenuconfig EMBEDDED 5381da177e4SLinus Torvalds bool "Configure standard kernel features (for small systems)" 5391da177e4SLinus Torvalds help 5401da177e4SLinus Torvalds This option allows certain base kernel options and settings 5411da177e4SLinus Torvalds to be disabled or tweaked. This is for specialized 5421da177e4SLinus Torvalds environments which can tolerate a "non-standard" kernel. 5431da177e4SLinus Torvalds Only use this if you really know what you are doing. 5441da177e4SLinus Torvalds 545ae81f9e3SChuck Ebbertconfig UID16 546ae81f9e3SChuck Ebbert bool "Enable 16-bit UID system calls" if EMBEDDED 54709337f50SDavid S. Miller depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) 548ae81f9e3SChuck Ebbert default y 549ae81f9e3SChuck Ebbert help 550ae81f9e3SChuck Ebbert This enables the legacy 16-bit UID syscall wrappers. 551ae81f9e3SChuck Ebbert 552b89a8171SEric W. Biedermanconfig SYSCTL_SYSCALL 5530847062aSRandy Dunlap bool "Sysctl syscall support" if EMBEDDED 55413bb7e37SEric W. Biederman default y 555b89a8171SEric W. Biederman select SYSCTL 556b89a8171SEric W. Biederman ---help--- 55713bb7e37SEric W. Biederman sys_sysctl uses binary paths that have been found challenging 55813bb7e37SEric W. Biederman to properly maintain and use. The interface in /proc/sys 55913bb7e37SEric W. Biederman using paths with ascii names is now the primary path to this 56013bb7e37SEric W. Biederman information. 561b89a8171SEric W. Biederman 56213bb7e37SEric W. Biederman Almost nothing using the binary sysctl interface so if you are 56313bb7e37SEric W. Biederman trying to save some space it is probably safe to disable this, 56413bb7e37SEric W. Biederman making your kernel marginally smaller. 565b89a8171SEric W. Biederman 56613bb7e37SEric W. Biederman If unsure say Y here. 567ae81f9e3SChuck Ebbert 5681da177e4SLinus Torvaldsconfig KALLSYMS 569979c6a1eSJesper Juhl bool "Load all symbols for debugging/ksymoops" if EMBEDDED 5701da177e4SLinus Torvalds default y 5711da177e4SLinus Torvalds help 5721da177e4SLinus Torvalds Say Y here to let the kernel print out symbolic crash information and 5731da177e4SLinus Torvalds symbolic stack backtraces. This increases the size of the kernel 5741da177e4SLinus Torvalds somewhat, as all symbols have to be loaded into the kernel image. 5751da177e4SLinus Torvalds 5761da177e4SLinus Torvaldsconfig KALLSYMS_ALL 5771da177e4SLinus Torvalds bool "Include all symbols in kallsyms" 5781da177e4SLinus Torvalds depends on DEBUG_KERNEL && KALLSYMS 5791da177e4SLinus Torvalds help 5801da177e4SLinus Torvalds Normally kallsyms only contains the symbols of functions, for nicer 5811da177e4SLinus Torvalds OOPS messages. Some debuggers can use kallsyms for other 582f9f97bc0SJesper Juhl symbols too: say Y here to include all symbols, if you need them 583f9f97bc0SJesper Juhl and you don't care about adding 300k to the size of your kernel. 5841da177e4SLinus Torvalds 5851da177e4SLinus Torvalds Say N. 5861da177e4SLinus Torvalds 5871da177e4SLinus Torvaldsconfig KALLSYMS_EXTRA_PASS 5881da177e4SLinus Torvalds bool "Do an extra kallsyms pass" 5891da177e4SLinus Torvalds depends on KALLSYMS 5901da177e4SLinus Torvalds help 5911da177e4SLinus Torvalds If kallsyms is not working correctly, the build will fail with 5921da177e4SLinus Torvalds inconsistent kallsyms data. If that occurs, log a bug report and 5931da177e4SLinus Torvalds turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 5941da177e4SLinus Torvalds Always say N here unless you find a bug in kallsyms, which must be 5951da177e4SLinus Torvalds reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 5961da177e4SLinus Torvalds you wait for kallsyms to be fixed. 5971da177e4SLinus Torvalds 598d59745ceSMatt Mackall 599712f47ceSGreg Kroah-Hartmanconfig HOTPLUG 600712f47ceSGreg Kroah-Hartman bool "Support for hot-pluggable devices" if EMBEDDED 601712f47ceSGreg Kroah-Hartman default y 602712f47ceSGreg Kroah-Hartman help 603712f47ceSGreg Kroah-Hartman This option is provided for the case where no hotplug or uevent 604712f47ceSGreg Kroah-Hartman capabilities is wanted by the kernel. You should only consider 605712f47ceSGreg Kroah-Hartman disabling this option for embedded systems that do not use modules, a 606712f47ceSGreg Kroah-Hartman dynamic /dev tree, or dynamic device discovery. Just say Y. 607712f47ceSGreg Kroah-Hartman 608d59745ceSMatt Mackallconfig PRINTK 609d59745ceSMatt Mackall default y 610d59745ceSMatt Mackall bool "Enable support for printk" if EMBEDDED 611d59745ceSMatt Mackall help 612d59745ceSMatt Mackall This option enables normal printk support. Removing it 613d59745ceSMatt Mackall eliminates most of the message strings from the kernel image 614d59745ceSMatt Mackall and makes the kernel more or less silent. As this makes it 615d59745ceSMatt Mackall very difficult to diagnose system problems, saying N here is 616d59745ceSMatt Mackall strongly discouraged. 617d59745ceSMatt Mackall 618c8538a7aSMatt Mackallconfig BUG 619c8538a7aSMatt Mackall bool "BUG() support" if EMBEDDED 620c8538a7aSMatt Mackall default y 621c8538a7aSMatt Mackall help 622c8538a7aSMatt Mackall Disabling this option eliminates support for BUG and WARN, reducing 623c8538a7aSMatt Mackall the size of your kernel image and potentially quietly ignoring 624c8538a7aSMatt Mackall numerous fatal conditions. You should only consider disabling this 625c8538a7aSMatt Mackall option for embedded systems with no facilities for reporting errors. 626c8538a7aSMatt Mackall Just say Y. 627c8538a7aSMatt Mackall 628708e9a79SMatt Mackallconfig ELF_CORE 629708e9a79SMatt Mackall default y 630708e9a79SMatt Mackall bool "Enable ELF core dumps" if EMBEDDED 631708e9a79SMatt Mackall help 632708e9a79SMatt Mackall Enable support for generating core dumps. Disabling saves about 4k. 633708e9a79SMatt Mackall 634e5e1d3cbSStas Sergeevconfig PCSPKR_PLATFORM 635e5e1d3cbSStas Sergeev bool "Enable PC-Speaker support" if EMBEDDED 636e5e1d3cbSStas Sergeev depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES 637e5e1d3cbSStas Sergeev default y 638e5e1d3cbSStas Sergeev help 639e5e1d3cbSStas Sergeev This option allows to disable the internal PC-Speaker 640e5e1d3cbSStas Sergeev support, saving some memory. 641e5e1d3cbSStas Sergeev 64232a93233SIngo Molnarconfig COMPAT_BRK 64332a93233SIngo Molnar bool "Disable heap randomization" 64432a93233SIngo Molnar default y 64532a93233SIngo Molnar help 64632a93233SIngo Molnar Randomizing heap placement makes heap exploits harder, but it 64732a93233SIngo Molnar also breaks ancient binaries (including anything libc5 based). 64832a93233SIngo Molnar This option changes the bootup default to heap randomization 64932a93233SIngo Molnar disabled, and can be overriden runtime by setting 65032a93233SIngo Molnar /proc/sys/kernel/randomize_va_space to 2. 65132a93233SIngo Molnar 652166124fdSIngo Molnar On non-ancient distros (post-2000 ones) N is usually a safe choice. 65332a93233SIngo Molnar 6541da177e4SLinus Torvaldsconfig BASE_FULL 6551da177e4SLinus Torvalds default y 6561da177e4SLinus Torvalds bool "Enable full-sized data structures for core" if EMBEDDED 6571da177e4SLinus Torvalds help 6581da177e4SLinus Torvalds Disabling this option reduces the size of miscellaneous core 6591da177e4SLinus Torvalds kernel data structures. This saves memory on small machines, 6601da177e4SLinus Torvalds but may reduce performance. 6611da177e4SLinus Torvalds 6621da177e4SLinus Torvaldsconfig FUTEX 6631da177e4SLinus Torvalds bool "Enable futex support" if EMBEDDED 6641da177e4SLinus Torvalds default y 66523f78d4aSIngo Molnar select RT_MUTEXES 6661da177e4SLinus Torvalds help 6671da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 6681da177e4SLinus Torvalds support for "fast userspace mutexes". The resulting kernel may not 6691da177e4SLinus Torvalds run glibc-based applications correctly. 6701da177e4SLinus Torvalds 6715dc8bf81SDavide Libenziconfig ANON_INODES 672448e3ceeSAdrian Bunk bool 6735dc8bf81SDavide Libenzi 6741da177e4SLinus Torvaldsconfig EPOLL 6751da177e4SLinus Torvalds bool "Enable eventpoll support" if EMBEDDED 6761da177e4SLinus Torvalds default y 677448e3ceeSAdrian Bunk select ANON_INODES 6781da177e4SLinus Torvalds help 6791da177e4SLinus Torvalds Disabling this option will cause the kernel to be built without 6801da177e4SLinus Torvalds support for epoll family of system calls. 6811da177e4SLinus Torvalds 682fba2afaaSDavide Libenziconfig SIGNALFD 683fba2afaaSDavide Libenzi bool "Enable signalfd() system call" if EMBEDDED 684448e3ceeSAdrian Bunk select ANON_INODES 685fba2afaaSDavide Libenzi default y 686fba2afaaSDavide Libenzi help 687fba2afaaSDavide Libenzi Enable the signalfd() system call that allows to receive signals 688fba2afaaSDavide Libenzi on a file descriptor. 689fba2afaaSDavide Libenzi 690fba2afaaSDavide Libenzi If unsure, say Y. 691fba2afaaSDavide Libenzi 692b215e283SDavide Libenziconfig TIMERFD 693b215e283SDavide Libenzi bool "Enable timerfd() system call" if EMBEDDED 694448e3ceeSAdrian Bunk select ANON_INODES 695b215e283SDavide Libenzi default y 696b215e283SDavide Libenzi help 697b215e283SDavide Libenzi Enable the timerfd() system call that allows to receive timer 698b215e283SDavide Libenzi events on a file descriptor. 699b215e283SDavide Libenzi 700b215e283SDavide Libenzi If unsure, say Y. 701b215e283SDavide Libenzi 702e1ad7468SDavide Libenziconfig EVENTFD 703e1ad7468SDavide Libenzi bool "Enable eventfd() system call" if EMBEDDED 704448e3ceeSAdrian Bunk select ANON_INODES 705e1ad7468SDavide Libenzi default y 706e1ad7468SDavide Libenzi help 707e1ad7468SDavide Libenzi Enable the eventfd() system call that allows to receive both 708e1ad7468SDavide Libenzi kernel notification (ie. KAIO) or userspace notifications. 709e1ad7468SDavide Libenzi 710e1ad7468SDavide Libenzi If unsure, say Y. 711e1ad7468SDavide Libenzi 7121da177e4SLinus Torvaldsconfig SHMEM 7131da177e4SLinus Torvalds bool "Use full shmem filesystem" if EMBEDDED 7141da177e4SLinus Torvalds default y 7151da177e4SLinus Torvalds depends on MMU 7161da177e4SLinus Torvalds help 7171da177e4SLinus Torvalds The shmem is an internal filesystem used to manage shared memory. 7181da177e4SLinus Torvalds It is backed by swap and manages resource limits. It is also exported 7191da177e4SLinus Torvalds to userspace as tmpfs if TMPFS is enabled. Disabling this 7201da177e4SLinus Torvalds option replaces shmem and tmpfs with the much simpler ramfs code, 7211da177e4SLinus Torvalds which may be appropriate on small systems without swap. 7221da177e4SLinus Torvalds 723ebf3f09cSThomas Petazzoniconfig AIO 724ebf3f09cSThomas Petazzoni bool "Enable AIO support" if EMBEDDED 725ebf3f09cSThomas Petazzoni default y 726ebf3f09cSThomas Petazzoni help 727ebf3f09cSThomas Petazzoni This option enables POSIX asynchronous I/O which may by used 728ebf3f09cSThomas Petazzoni by some high performance threaded applications. Disabling 729ebf3f09cSThomas Petazzoni this option saves about 7k. 730ebf3f09cSThomas Petazzoni 731f8891e5eSChristoph Lameterconfig VM_EVENT_COUNTERS 732f8891e5eSChristoph Lameter default y 733f8891e5eSChristoph Lameter bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 734f8891e5eSChristoph Lameter help 7352aea4fb6SPaul Jackson VM event counters are needed for event counts to be shown. 7362aea4fb6SPaul Jackson This option allows the disabling of the VM event counters 7372aea4fb6SPaul Jackson on EMBEDDED systems. /proc/vmstat will only show page counts 7382aea4fb6SPaul Jackson if VM event counters are disabled. 739f8891e5eSChristoph Lameter 74041ecc55bSChristoph Lameterconfig SLUB_DEBUG 74141ecc55bSChristoph Lameter default y 74241ecc55bSChristoph Lameter bool "Enable SLUB debugging support" if EMBEDDED 743f6acb635SChristoph Lameter depends on SLUB && SYSFS 74441ecc55bSChristoph Lameter help 74541ecc55bSChristoph Lameter SLUB has extensive debug support features. Disabling these can 74641ecc55bSChristoph Lameter result in significant savings in code size. This also disables 74741ecc55bSChristoph Lameter SLUB sysfs support. /sys/slab will not exist and there will be 74841ecc55bSChristoph Lameter no support for cache validation etc. 74941ecc55bSChristoph Lameter 75081819f0fSChristoph Lameterchoice 75181819f0fSChristoph Lameter prompt "Choose SLAB allocator" 752a0acd820SChristoph Lameter default SLUB 75381819f0fSChristoph Lameter help 75481819f0fSChristoph Lameter This option allows to select a slab allocator. 75581819f0fSChristoph Lameter 75681819f0fSChristoph Lameterconfig SLAB 75781819f0fSChristoph Lameter bool "SLAB" 75881819f0fSChristoph Lameter help 75981819f0fSChristoph Lameter The regular slab allocator that is established and known to work 76034013886SChristoph Lameter well in all environments. It organizes cache hot objects in 76181819f0fSChristoph Lameter per cpu and per node queues. SLAB is the default choice for 76234013886SChristoph Lameter a slab allocator. 76381819f0fSChristoph Lameter 76481819f0fSChristoph Lameterconfig SLUB 76581819f0fSChristoph Lameter bool "SLUB (Unqueued Allocator)" 76681819f0fSChristoph Lameter help 76781819f0fSChristoph Lameter SLUB is a slab allocator that minimizes cache line usage 76881819f0fSChristoph Lameter instead of managing queues of cached objects (SLAB approach). 76981819f0fSChristoph Lameter Per cpu caching is realized using slabs of objects instead 77081819f0fSChristoph Lameter of queues of objects. SLUB can use memory efficiently 77134013886SChristoph Lameter and has enhanced diagnostics. 77281819f0fSChristoph Lameter 77381819f0fSChristoph Lameterconfig SLOB 77484a01c2fSPaul Mundt depends on EMBEDDED 77581819f0fSChristoph Lameter bool "SLOB (Simple Allocator)" 77681819f0fSChristoph Lameter help 77737291458SMatt Mackall SLOB replaces the stock allocator with a drastically simpler 77837291458SMatt Mackall allocator. SLOB is generally more space efficient but 77937291458SMatt Mackall does not perform as well on large systems. 78081819f0fSChristoph Lameter 78181819f0fSChristoph Lameterendchoice 78281819f0fSChristoph Lameter 783125e5645SMathieu Desnoyersconfig PROFILING 784125e5645SMathieu Desnoyers bool "Profiling support (EXPERIMENTAL)" 785125e5645SMathieu Desnoyers help 786125e5645SMathieu Desnoyers Say Y here to enable the extended profiling support mechanisms used 787125e5645SMathieu Desnoyers by profilers such as OProfile. 788125e5645SMathieu Desnoyers 789125e5645SMathieu Desnoyersconfig MARKERS 790125e5645SMathieu Desnoyers bool "Activate markers" 791125e5645SMathieu Desnoyers help 792125e5645SMathieu Desnoyers Place an empty function call at each marker site. Can be 793125e5645SMathieu Desnoyers dynamically changed for a probe function. 794125e5645SMathieu Desnoyers 795fb32e03fSMathieu Desnoyerssource "arch/Kconfig" 796fb32e03fSMathieu Desnoyers 7971da177e4SLinus Torvaldsendmenu # General setup 7981da177e4SLinus Torvalds 799ee7e5516SDmitry Baryshkovconfig HAVE_GENERIC_DMA_COHERENT 800ee7e5516SDmitry Baryshkov bool 801ee7e5516SDmitry Baryshkov default n 802ee7e5516SDmitry Baryshkov 803158a9624SLinus Torvaldsconfig SLABINFO 804158a9624SLinus Torvalds bool 805158a9624SLinus Torvalds depends on PROC_FS 8060f389ec6SChristoph Lameter depends on SLAB || SLUB_DEBUG 807158a9624SLinus Torvalds default y 808158a9624SLinus Torvalds 809ae81f9e3SChuck Ebbertconfig RT_MUTEXES 810ae81f9e3SChuck Ebbert boolean 811ae81f9e3SChuck Ebbert select PLIST 812ae81f9e3SChuck Ebbert 8131da177e4SLinus Torvaldsconfig TINY_SHMEM 8141da177e4SLinus Torvalds default !SHMEM 8151da177e4SLinus Torvalds bool 8161da177e4SLinus Torvalds 8171da177e4SLinus Torvaldsconfig BASE_SMALL 8181da177e4SLinus Torvalds int 8191da177e4SLinus Torvalds default 0 if BASE_FULL 8201da177e4SLinus Torvalds default 1 if !BASE_FULL 8211da177e4SLinus Torvalds 82266da5733SJan Engelhardtmenuconfig MODULES 8231da177e4SLinus Torvalds bool "Enable loadable module support" 8241da177e4SLinus Torvalds help 8251da177e4SLinus Torvalds Kernel modules are small pieces of compiled code which can 8261da177e4SLinus Torvalds be inserted in the running kernel, rather than being 8271da177e4SLinus Torvalds permanently built into the kernel. You use the "modprobe" 8281da177e4SLinus Torvalds tool to add (and sometimes remove) them. If you say Y here, 8291da177e4SLinus Torvalds many parts of the kernel can be built as modules (by 8301da177e4SLinus Torvalds answering M instead of Y where indicated): this is most 8311da177e4SLinus Torvalds useful for infrequently used options which are not required 8321da177e4SLinus Torvalds for booting. For more information, see the man pages for 8331da177e4SLinus Torvalds modprobe, lsmod, modinfo, insmod and rmmod. 8341da177e4SLinus Torvalds 8351da177e4SLinus Torvalds If you say Y here, you will need to run "make 8361da177e4SLinus Torvalds modules_install" to put the modules under /lib/modules/ 8371da177e4SLinus Torvalds where modprobe can find them (you may need to be root to do 8381da177e4SLinus Torvalds this). 8391da177e4SLinus Torvalds 8401da177e4SLinus Torvalds If unsure, say Y. 8411da177e4SLinus Torvalds 8420b0de144SRobert P. J. Dayif MODULES 8430b0de144SRobert P. J. Day 844826e4506SLinus Torvaldsconfig MODULE_FORCE_LOAD 845826e4506SLinus Torvalds bool "Forced module loading" 846826e4506SLinus Torvalds default n 847826e4506SLinus Torvalds help 84891e37a79SRusty Russell Allow loading of modules without version information (ie. modprobe 84991e37a79SRusty Russell --force). Forced module loading sets the 'F' (forced) taint flag and 85091e37a79SRusty Russell is usually a really bad idea. 851826e4506SLinus Torvalds 8521da177e4SLinus Torvaldsconfig MODULE_UNLOAD 8531da177e4SLinus Torvalds bool "Module unloading" 8541da177e4SLinus Torvalds help 8551da177e4SLinus Torvalds Without this option you will not be able to unload any 8561da177e4SLinus Torvalds modules (note that some modules may not be unloadable 857f7f5b675SDenys Vlasenko anyway), which makes your kernel smaller, faster 858f7f5b675SDenys Vlasenko and simpler. If unsure, say Y. 8591da177e4SLinus Torvalds 8601da177e4SLinus Torvaldsconfig MODULE_FORCE_UNLOAD 8611da177e4SLinus Torvalds bool "Forced module unloading" 8621da177e4SLinus Torvalds depends on MODULE_UNLOAD && EXPERIMENTAL 8631da177e4SLinus Torvalds help 8641da177e4SLinus Torvalds This option allows you to force a module to unload, even if the 8651da177e4SLinus Torvalds kernel believes it is unsafe: the kernel will remove the module 8661da177e4SLinus Torvalds without waiting for anyone to stop using it (using the -f option to 8671da177e4SLinus Torvalds rmmod). This is mainly for kernel developers and desperate users. 8681da177e4SLinus Torvalds If unsure, say N. 8691da177e4SLinus Torvalds 8701da177e4SLinus Torvaldsconfig MODVERSIONS 8710d541643SSam Ravnborg bool "Module versioning support" 8721da177e4SLinus Torvalds help 8731da177e4SLinus Torvalds Usually, you have to use modules compiled with your kernel. 8741da177e4SLinus Torvalds Saying Y here makes it sometimes possible to use modules 8751da177e4SLinus Torvalds compiled for different kernels, by adding enough information 8761da177e4SLinus Torvalds to the modules to (hopefully) spot any changes which would 8771da177e4SLinus Torvalds make them incompatible with the kernel you are running. If 8781da177e4SLinus Torvalds unsure, say N. 8791da177e4SLinus Torvalds 8801da177e4SLinus Torvaldsconfig MODULE_SRCVERSION_ALL 8811da177e4SLinus Torvalds bool "Source checksum for all modules" 8821da177e4SLinus Torvalds help 8831da177e4SLinus Torvalds Modules which contain a MODULE_VERSION get an extra "srcversion" 8841da177e4SLinus Torvalds field inserted into their modinfo section, which contains a 8851da177e4SLinus Torvalds sum of the source files which made it. This helps maintainers 8861da177e4SLinus Torvalds see exactly which source was used to build a module (since 8871da177e4SLinus Torvalds others sometimes change the module source without updating 8881da177e4SLinus Torvalds the version). With this option, such a "srcversion" field 8891da177e4SLinus Torvalds will be created for all modules. If unsure, say N. 8901da177e4SLinus Torvalds 8911da177e4SLinus Torvaldsconfig KMOD 892baabaae9SJohannes Berg def_bool y 8931da177e4SLinus Torvalds help 894baabaae9SJohannes Berg This is being removed soon. These days, CONFIG_MODULES 895baabaae9SJohannes Berg implies CONFIG_KMOD, so use that instead. 8961da177e4SLinus Torvalds 8970b0de144SRobert P. J. Dayendif # MODULES 8980b0de144SRobert P. J. Day 8991da177e4SLinus Torvaldsconfig STOP_MACHINE 9001da177e4SLinus Torvalds bool 9011da177e4SLinus Torvalds default y 9021da177e4SLinus Torvalds depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 9031da177e4SLinus Torvalds help 9041da177e4SLinus Torvalds Need stop_machine() primitive. 9053a65dfe8SJens Axboe 9063a65dfe8SJens Axboesource "block/Kconfig" 907e98c3202SAvi Kivity 908e98c3202SAvi Kivityconfig PREEMPT_NOTIFIERS 909e98c3202SAvi Kivity bool 910e260be67SPaul E. McKenney 911e260be67SPaul E. McKenneyconfig CLASSIC_RCU 91221bbb39cSPaul E. McKenney def_bool !PREEMPT_RCU 913e260be67SPaul E. McKenney help 914e260be67SPaul E. McKenney This option selects the classic RCU implementation that is 915e260be67SPaul E. McKenney designed for best read-side performance on non-realtime 91621bbb39cSPaul E. McKenney systems. Classic RCU is the default. Note that the 91721bbb39cSPaul E. McKenney PREEMPT_RCU symbol is used to select/deselect this option. 918